Abstract: Sixty-two cultures from the Agricultural Research Service (ARS) Culture Collection and 10 cultures isolated from soil and water samples in Illinois were screened for their ability to convert agricultural oils to value-added industrial chemicals. A new compound, 7,10-dihydroxy-8(E)-octadecenoic acid (DOD), was produced from oleic acid at a yield of greater than 60% by bacterial strain PR3 which was isolated from a water sample in Morton, IL. To our knowledge, DOD has not been previously reported. The optimum time, pH and temperature for the production of DOD were 2 days, 7.0, and 30°C, respectively. The production of DOD is unique in that it involves hydroxylation at two positions and rearrangement of the double bond of the substrate molecule.

Abstract: The alk genes from the catabolic OCT plasmid of Pseudomonas oleovorans, which encode the enzymes involved in the oxidation of n-alkanes to carboxylic acids, were introduced into E. coli W3110. The resulting recombinant converts n-octane in a two-liquid phase medium into the corresponding alkanoate and excretes this compound into the aqueous phase. The rate of octanoic acid production by the recombinant E. coli is equal to or better than the alkane oxidation rate of P. oleovorans, suggesting that two-liquid phase fermentations with E. coli might have future industrial applications.

Abstract: Aspects of aerobic degradation of aromatics by micro-organisms biodeterioration of fuels biodegradation of nitriles and cyanide the fate of chemicals in soil biosynthesis and structure of lignocellulose enzymes and activities involved in straw saccharification uses and potential of lignocellulose commercial aspects of bioconversion technology.

Abstract: Development of production methods for commercial manufacture of bioherbicides is in its infancy. However, fermentation of fungi for use in industrial processes, such as the manufacture of wine and beer, bioconversion of organic molecules, and antibiotic production, is well-known and established technology (33,35,37,50). Interestingly, production of a bioherbicide differs from many conventional fermentation processes, because for bioherbicides the final product is the living biomass of the plant pathogen itself rather than a fermentation byproduct. Not only is high biomass yield essential for commercialization of these products, but the biomass must also be viable, stable in a package on the distributor’s shelf, simple for the farmer to apply, and effective under the widely varying environmental conditions encountered in production agriculture.

Abstract: In the bioconversion studies of molasses and sugarbeet pulp to single cell protein by four Candida spp. (utilis, tropicalis, parapsilosis and solani) maximum protein content of 37.5 and 43.4% was achieved from the two substrates, respectively, in 48 h. Candida utilis and C. tropicalis performed better than the other yeasts. The maximum bioconversion efficiency for molasses (43%) was given by C. parapsilosis and for beet pulp (46%) by C. tropicalis in 48 h batch flask fermentations. The bioconversion of beet pulp under controlled conditions was studied using C. tropicalis in a 51 fermentor, which gave 29 and 48% product recovery with 39 and 25% protein level, in a two- and one-stage process, respectively. The one-stage process (simultaneous saccharification and fermentation) was also run in a larger volume and gave 50% product recovery with 29% protein content. The results are discussed in terms of biomass yield, protein content and bioconversion efficiency of yeasts under each condition.

Abstract: Summary: Bacterial conversion of 4-chlorobiphenyl (4-CB) usually proceeds through a pathway involving an initial oxidation of the unsubstituted ring in the 2,3 position followed by a 1,2 meta-cleavage. The meta-cleavage product (MCP) is converted through a single hydrolysis step into chlorobenzoic acid. However, several other acidic metabolites that were not expected as part of this pathway have already been described. In this paper, we used strains of Pseudomonas putida carrying cloned genes from Pseudomonas testosteroni B-356 that are involved in polychlorinated biphenyl (PCB) degradation to demonstrate that several acidic metabolites found in the culture media of various bacteria grown in the presence of 4-CB result from alternative novel bioconversion pathways of MCP. The degradation products of MCP through these pathways were identified as analogues with saturated or shorter side chains or as 4′-chlorophenyl-2-picolinic acid; pathways leading to their formation are proposed.

Abstract: This paper reports on the possibility of obtaining C-6 (hexanal) and C-10 (2,4-dedadienal) volatile aldehydes by degradation of linoleic acid (C18∶2 Δ 9–12) under the action of the intrinsic enzyme systems found in apple pomace. More aroma compounds are produced by micronization of the pomace and by adding SO2 (60 ppm) and vitamin C (500 ppm), thereby synergistically counteracting oxidation of phenolic compounds, which is a limiting factor in bioconversion.

Abstract: This article describes a process for microbial hydroxylation of simvastatin by a Nocardia sp. Simvastatin (Zocor) belongs to the family of HMGCoA reductase inhibitors used as cholesterol-lowering drugs. Studies at 14 L scale showed that high substrate (simvastatin) concentrations inhibited product formation; consequently, continuous slow feeding of the substrate was introduced to maintain low residual simvastatin concentrations. Dissolved oxygen levels above 50% air saturation were desirable for the biotransformation. The process was scaled up to 19,000-L fermentors using an on-line filter sterilization system for substrate feeding. The feed rate was regulated by off-line high-pressure liquid chromatography (HPLC) assays to keep the substrate concentration below 20 mg/L. Intermittent addition of nutrients helped to boost the bioconversion rate to give final titers of 400 mg/L 6-beta-hydroxymethyl simvastatin. Enrichment of the nutrient medium led to bioconversion titers of 800 mg/L 6-beta-hydroxymethyl simvastatin. Bioconversion efficiencies (desired product/substrate) of 22-25% with a ratio of desired product/side products of 0.7 were obtained by this process.

Abstract: Bioconversion of α-damascone (compound 1) was studied with four strains of Botrytis cinerea in grape must (pH 3.2). As biotransformation products of compound 1, 3-oxo-α-damascone, cis- and trans-3-hydroxy-α-damascone, γ-damascenone, 3-oxo-8, 9-dihydro-α-damascone, and cis- and trans-3-hydroxy-8,9-dihydro-α-damascone were identified. In addition, acid-catalyzed chemical transformation of compound 1 to the diastereomers of 9-hydroxy-8,9-dihydro-α-damascone was observed. Identifications were performed by capillary gas chromatography (HRGC) and coupled HRGC techniques, i.e., on-line HRGC-mass spectrometry and HRGC-Fourier transform infrared spectroscopy, after extractive sample preparation.

Abstract: The reaction steps involved in the bioconversion of a chemically synthesized precursor, acid (D,L-ATC), to L-cysteine and the properties of the involved enzymes were investigated. It was found that the conversion consisted of two steps, i. e., D,L-ATC to S-carbamyl-L-cysteine (S-C-L-cysteine) and S-C-L-cysteine to L-cysteine, and the S-C-L-cysteine was an intermediate between them. While the enzymes involved in the reactions were induced by the addition of D,L-ATC as an inducer, S-C-L-cysteine induced only the enzyme involved in the latter step. The conversion of S-C-L-cysteine to L-cysteine could be also carried out in the presence of hydroxylamine and its rate was much faster than that by the corresponding enzyme. On the other hand, L-cysteine (or L-cystine) was decomposed to evolve by the enzyme considered to be a kind of desulfhydrase. However, hydroxylamine was a perfect inhibitor for this enzyme.

Abstract: Bioconversion of wheat straw by solid-substrate fermentation (SSF) withCoriolus versicolor was optimized by varying its physiological parameters. Selective delignification (more lignin than holocellulose degradation) and increases in crude protein (CP) content andin vitro dry matter digestibility (IVDMD) were taken as the criteria to select optimum levels of these parameters. The fungus behaved optimally under the following set of cultural and nutritional conditions: pH 5.5, moisture level 55%, temperature 30 °C, duration of fermentation 21 d, form of inoculum—grain culture, turning frequency—once at mid-incubation, urea (nitrogen source) 1.5% (sterile) or 3.0% (nonsterile), single superphosphate (phosphorus+sulfur source) 1.0%, no addition of free polysaccharides (as whey or molasses). A maximum of 17.5% increase in IVDMD involving 4.3% degradation of lignin, was attained in the optimized SSF under laboratory conditions. The digestibility improvement could be further increased by using a substrate preteatment (physical/chemical/biological) in the following order of preference: NaOH treatment, urea or urine treatment, ensiling, steaming, grinding. For practical farm applications, urea treatment and ensiling appeared most feasible. The laboratory optimized process was also scaled up to 4 kg (sterile and unsterile) and 50 kg (unsterile) fermentations.

Abstract: Process for the production of vanillin, characterised in that a culture of Basidiomycete fungus of the genus Pycnoporus or of its variants and mutants is produced in a culture medium to which a benzene-related precursor of vanillin has been added and the vanillin produced by bioconversion of the said precursor is recovered.

Abstract: The ability of the yeastSaccharomyces cerevisiae to bioconvert stereo-selectively octyl-4-chloroacetoacetate (OCA) into the corresponding chiral alcohol, precursor of L-carnitin, an important physiological agent, was investigated.

Abstract: Dehydrogenation of hydrocortisone by agitated suspensions of free and immobilized cells of Arthrobacter simplex ATCC 6946 was investigated under controlled ultrasonic irradiation at a frequency of 20 kH(z). The microbial conversion was optimized first with respect to mechanical agitation and subsequently with respect to an additionally superimposed sonication. The optimization of ultrasound intensity and its mode of application were established at a level which maintained the structural integrity of the cells as well as their biocatalytic activity. Various regimes of ultrasound at power densities of 0.030-0.120 W/mL were applied in systems of soluble (0.4 g/L) and excess (1 g/L) hydrocortisone and only a moderate enhancement of the bioconversion by free cells was observed. This result was explained by a better ultrasound-induced dispersal of microscopic clumps of cells and self-adhering clusters of the steroids. However, a quite significant enhancement effect was obtained in bioconversion systems of soluble substrate by gel-entrapped cells. This enhancement was explained by a phonophoretic effect associated with ultrasound-facilitated diffusion of the substrates-oxygen and hydrocortisone-within the gel beads.

Abstract: A novel aqueous two-phase system, based on polyethyleneglycol (PEG) and monosodium glutamate, was tested for the 1-dehydrogenation of hydrocortisone-based substrates. This system led to higher substrate solubilities and biocatalyst/steroid separation levels when compared with alternative systems. The addition of short-chain monohydric alcohols resulted in higher solubilities and more favourable partition coefficients for the tested substrates. Bioconversion activities in PEG/glutamate systems with 2,5% (v/v) methanol were comparable to those measured in monophasic buffer-methanol medium.

Abstract: The United States should develop alternative feedstocks for production of organic chemicals as a step in reducing dependence on foreign oil and to protect the US economy from oil supply disruptions. Potential alternative feedstocks include lignocellulose, polysaccharides, and sugars. These feedstocks can be converted to organic chemicals via bioconversion; sources include feedstock crops (lignocellulosic, polysac-charide, and sugar crops grown specifically for use as feedstocks in organic chemicals production) and industrial, municipal, and agricultural wastes. A wide range of chemicals can be produced via bioconversion, including existing commodity chemicals and entirely new chemicals and polymers. In this review, potential feedstocks are described and are shown to be sufficient to support a bioconversion -- based organic chemicals industry. In addition, the current US organic chemicals industry is briefly described. The potential of bioconversion for production of existing commodity chemicals and entirely new chemicals and polymers is discussed. 228 refs., 21 tabs.

Abstract: Arthrobacter simplex ATCC 6946 (viable cells) was immobilized in a calcium polygalacturonate gel. The trapped cells were used for repeated batchwise bioconversion of steroids. Reichstein's compound S and hydrocortisone were dehydrogenated introducing a double bond between C1 and C2 of ring A. The products 1-dehydro S and prednisolone, respectively, were identified by high pressure liquid chromatography. Steroid dehydrogenase activity increased in the system when an artificial electron acceptor, such as menadione (vitamin K3) was present in the reaction mixture. An airlift-type reactor was used to bioconvert up to 90% of substrate in 15 min, under optimal conditions. The gel entrapped cell preparations were used for repeated batch bioconversion during 30 days; 69 batch bioconversions for Reichstein's compound S were performed during 15 days of operation of the reactor. The operational stability of the process and the feasibility of repeated batch bioconversions was shown to be comparable to similar processes.

Abstract: Method and apparatus are provided for the bioconversion of toxic substrates with increased yields of product. The invention makes use of immobilized cells as biocatalyst and complexing agent in either dissolved or solid form. The invention also employs various schemes and apparatus for separating immobilized cells and complexing agent for recycle and re-use in bioconversion reactions. A preferred embodiment of the invention produces improved yields and titers of L-phenylacetyl carbinol by the bioconversion of acetaldehyde using yeast cells.

Abstract: The biotransformation of 2-acetylthiophene by 800 strains of micromycetes has been investigated. Among them, 460 strains have been selected on solid media and cultivated in a liquid synthetic medium. Of these, 106 strains were able to completely deplete 2-acetylthiophene with or without production of intermediary metabolites. 2-Thienylglyoxylic acid was not detected but 72 strains produced 2-thiophenecarboxylic acid. Among them, eight strains have been selected for further optimization of this bioconversion.